Motor-control system.



H113. WHITE.

MOTOR GONTROL SYSTEM.

APPLICATION FILED JUNE 19, 1909.

Patented Nov. 14, 1911.

JNYENTUR I 3 HARULD It WHITE.

W2? MQ ATTY H. E. WHITE.

MOTOR CONTROL SYSTEM.

APPLICATION FILED JUNE 19, 1909.

Patented Nbv.14,1911.

2 SHEETSSHEET 2.

Q: 5 I llllllllllll q INS/ENTER HAHULD .E'. WHITE.

mmz'ssrs':

UNITED sTA'rEs PAT NT OFFICE.

HAROLD E. WHITE, OF SCHENECTADY, NEW YORK, ASSIGN OR TO GENERAL ELECTRICCOMPANY A CORPORATION OF YORK.

LTOTOR-CONTROL. SYSTEM.

Specification of Letters Patent. Patented Nov. 14, 1911. I

Application filed June 19, 1909. Serial No. 503,058.

' for electric motors and particularly to those systems of control inwhich the motor to be controlled is braked dynamically by connecting itin a closed circuit through more or less resistance.

5 It is an object of my invent-ion to provide a new and'improved systemof control of this general type and to this end I provide an arrangementof which the system herein shown and described is an illustrativeemzoxb'odi'ment.

- By my invention the control of the motor both for power and brakingoperation is effected from a controllingdevice, which in the same 0erative positions is easily arranged by t e operator for either power orbraking'control of the motor.

'In the particular form of my invention herein set forth I provide a.plurality of electrically controlled switches or contactors .forconnecting the motor to be controlled to a source of current, regulating.the amount of resistance in the motor circuit and shortcircuitingthe'motor through resistance for dynamic braking, these contactors beingunder the' control of a master switch provided with means for renderingthe master switch operative in the same positions for.

either power or braking control of the motor. Furthermore, I have shownthe 40 motor as provided with a friction brake bi- I Cased t0 brakingposition and releasedby an electromagnet which is energized at all timesduring ower operation and is energized during ynamic braking, exceptwhen all of the resistance is short-circuited in the dy-.

namic braking circuit The resistance controlling contactors in thesystem of control shown are arranged in a well-lmown man-' ner'forautomatic closing under the control of relays responsive to the; currentin the motor circuit, these relays being operativei during both poweroperation and dynamic braking'of the motor. In connection with theserela s, I have introduced anew f e a '55 ture whic consists in providingauxiliary which is operated from the ban series coils energized duringdynamic braking, but notduring power operation, which, in ,theparticular system hereinafter described, make the current limit controlof, the successive closin of the'resist'ance con- 0 trollin contactorsifferent, during power operation fromwha't itis duringdynamic brakingoperation.

. The form and arrangement of the embodiment of my improved system ofcontrol 3 shown in this application and its manner of operation will beunderstood from the following description taken in connection with theaccompanying drawings, in 'which Figure 1 is a diagrammaticillustrationof 40 a system of control having my invention embodiedtherein; Fig. 2 is a front elevation of a portion of the master switchshowing the I handle; Fig. 3 is an elevation at right angles to Fig. 2,certain parts being shown in crosssection; Fig. 4 is a diagram showingthe power connections of the motor; and Fig. 5

is a diagram showing the dynamic braking connections or the motor. i

Referring to the drawings, the motor to 30 be controlled is shown as ofthe compound type havin an armature A, seriesfield F and shunt eld Itwill be obvious, however, that my invention is not limited to use inconnection with ,this type of motor. The '85 resistance, interposed inthe motor circuit in starting and for purposes of control, is shown asmade up ofsecti'ons R R ,R ,R* and R which are, respectively,short-circuited by, electrically controlled switches or "so contactors1, 2, 3, 4 and 5. The armature is connected in'circuit withtheresistun'ce and series field for one direction ofrotation by the linecontactors L and L andfor the other direction of rotation by linecontactors L and L. The contactor L connects the motor circuit to thesource of current and the contactor D, when closed, short-circuits themotor through the resistance R? to R for dynamic braking; thesecontactors 19 and L are interlocked as shown, so that $1- multaneousclosing of them is impossible. The contactors are controlled from a.master switch K, which may be of the drum type, thisbeing showndeveloped in a well- 5 known conventional manner, as provided withfingers a to m with which segments on the drum coii rate. The masterswitch is provided wit a circuit changingl device,

0, these parts being best shown in detail in bi s. 2 and 3. The shaft 10ofthe drum 0 the master switch is provided at its top with a beveledgear 11, with which a beveled gear segment 12 coiiperates, the latterbeing integral with the handle 13 of the master switch, which is mountedon 'a horizontal axis for movement in a vertical plane. As shown inFigs. 2 and 3, the handle 13 is mounted on :1 lug which projects from a'frame 1 1 secured to the top of the master switch casing, a nut 15serving to hold the handle upon the lu The frame 14 carries, or may havemade integral therewith, a box 16, within which the parts of certaincircuit changing switches are mounted. In the particular arrangementshown, a rod 17 is arranged for sliding movement within the box 16, oneof the rod being arranged to slide within a boss 18, projecting from theinside of the cover 19, while the other end of the rod proiects throughthe lug upon which the handle 13 is mounted. The outer end of the rod 17is engaged by lever 20 pivoted at 21 on the handle 13 and extendingupwardly into a hand piece 22 adapted to be gripped by the operator. Thespring 23 normally biases the lever 20 to the position shown in Figs. 1and 3, in which said lever forces the rod 17 into the box 16 against theten sion of the spring 25 mounted between the inside of the cover 19 anda collar 26 secured on the rod 17. Arranged for free slidingmovement onthe rod 17 are contact disks 27, 28, 29 and 30, which may be of thewell-known form used in connection with the auxiliary switches employedon contactors. These contact disks -27 to 30 codperate with fixedcontact members 31 which may be mounted in insulation 32 on the insideof the box 16. Between the disks 27 and 28 and between the disks 29 and30 springs 34 and 35 are located, which tend to force the disks of each,pair apart into engagement with collars fixed upon the rod 17, asclearly shown in Fig. 3. The arrangement of the disks 27 to 30 and thefixed contact members 31 is such that when the grip 22 is released, andthe lever 20 assumes the position shown in Fi 1 and 3, the disks 28 and30 bridge their cooperating fixed contacts 31; and when the grip 22 isgrasped by the operator, and moved against the tension of the spring 23,thereby moving the lever 20 away from the handle 13 and allowing the rod17 to slide in response to the pressure of the spring 25, the disks 27and 29 bridge their coiiperating contacts 31. It is, therefore, evidentthat the circuit changing device is biased to a certain position by thespring 23 and that in order to move said circuit changing device to itsother position it is necessary forrthe operator to press the grip 22toward the'handle 13.

t may be desirable in certain instances to provide a position orpositions of the master switch in which it can be left by the operatorfor power operation of the motor.

This can easily be provided for by arrangin the full speed position ofthe controller for either direction of rotation of the motor. From aninspection of the develo ment of the master switch shown in Fig. 1 itwill be seen that no change in the control circuits is made by it in thesixth' on positions from the connections made in the fifth on positions.This siXthposit-ion is the full speed position, in which the operatormay leave the master switch without the necessity of holding the grip 22against the handle 13 in order to insure power operation. The lastmentioned feature is made possible by means of the segment 36 which, asis clearly shown in Figs. 2 and 3, is mounted on supports 37 extending"upwardly from the frame 14, lugs 38 being provided on the ends of thesegment 36 in such a position that when the handle 13 is turned to itslugs 38 may be arranged to 006 crate with the lever 20 in otherpositions 0 the handle for the same purpose.

The notching relays by which the successive closing of the resistancecontrolling ccntactors 1 to 4 is controlled are shown at P and P Themanner in which these relays P and P cooperate with the resistancecontrolling contactors is that set forth in a co-pending ap lication inthe name of Archibald S. gubitt', Serial 'No. 431342, filed May 7, 1908,and assigned to the same assignee as this application. In the systemherein shown, the relays P and P are provided with main series coils pand g), respectively, and with auxiliaryseries coils 0 and 0 Duringpower operation the coils 79 and p only are energized, while duringdynamic braking the motor current passes through the auxiliary seriescoils o and 0 as well as the main series coils p and f, these coilsbeing so wound that the fields produced by them assist one another. Withtwo series coils on each relay arranged in this way, the current in themotor circuit during power operation willbe allowed to rise to a'highervalue than during dynamic braking operation, which under someconditions-is desirable, owingto the fact that at p the mechanicalfriction of the motor and driven parts has to be overcome. during poweroperation, while during dynamic braking this friction helps to retardthe motor. Under some conditions, however, it may be desirable to havethe two series coils on the relays differentially wound in order to varythe effect of these relays under different conditions of motoroperation, and it is my intention in this application to cover sucharrangements broadly. The motor circuits are shown as supplied withcurrent from a suitable source through a switch S, while the controlcircuits of the system are supplied with current from a source throughthe switch .9. The motor A is, in the particular system herein shown,provided with a friction brake .B, illustrated in the usual diagrammaticmanner as biased to braking position by a spring 5 and as adapted to bereleased by the energization of an electromagnet b The contactors L, D,L L L", L, 1, 2, 3, 4 and 5 are shown as provided with auxiliaryswitches or interlocks which make and break connections in the controlcircuits. These auxiliary switches are shown in the usual conventionalmanner as .of the disk type, which lends itself readily to diagrammaticillustration. The order in which the auxiliary switches of any contactoropen and close when the contactor operates will be clear from thedrawing and the description of the operation of the system herein aftergiven.,

The arrangement of control circuits will best be understood from adescription of the operation of thecontrol system which will now begiven. The switches S and 8 being closed and the" operator desiring toconnect the motor to-the source for power operation, let us suppose thatthe handle has been gripped so as to move the lever 20 outwardly andallow the rod 17 carrying the disk 27 to 30 to move to its left-handposition, or,'in other words, to the other posi-- tion from that shownin Figs. 1 and 3; let us assume, also, that the handle has been -movedto bring the drum of the master switch into engagement on the right handside of the fingers a to m inclusive in the 1st position. Under thiscondition a circuit is completed from the side of the source through theswitch 8, wire 40, finger m, thence to finger Z through the cooperatingsegments, through wire 41, contact disk 29,

wire 42, through the brake magnet 6 wire 43, return wire 44 and switch 8to the side of the source. The brake Bis, therefore, released. A circuitis simultaneously completed from the positive side of the source throughthe wire 46, contact disk 27, wire interlock on the contactor D,actuating coil of the contactor L through the return wire 44 back to theside of the source. The contactor L, therefore, closes. Another circuitis completed from the contacts controlled by the disk 27 through thewire 48 to finger d, thence to finger e, through the cooperatingsegments, then through wire 49, actuating coil of the contactor L lowerinterlock on the contactor L actuating coil of the contactor L lowerinterlock on the contactor L wire 50, contact of notching relav P shuntcoil of the notching relay P, wire 51 and the wire 44 to the side of thesource. The contactors L and L therefore, close and the motor isconnected to the source through allof the resistance R to R as shown inFig. 4, the main series coils p and p of the relays P and P being, underthis condition, connected in the motor circuit. The switch L ,inclosing, closed its middle interlock and opened its lower one, therebyshifting its actuating coil from. connection to the wire 50 toconnection directly to the return wire 44, thereby rendering the sameindependent of the notching relays. The contactor L in closing openedits lower interlock and closed itsupper one; the openlng of the lowerinterlock positively prevents the closing of the contactors L and L andthe closing of the upper interlock connects the wire 49 through the wire54 to the finger g on the master switch 'K. Opening of the interlock onthe switch L positively prevents the-energization of the actuating coilof the contactor D. If the master switch is moved to its 2nd positionthe fingers g and h are connected by their cooperating segments and thewire 55 leading from the finger is energized, thereby completmg acircult through the actuating coil of contactor 1, through the ,lowerinterlock on this contactor, through wire 56,'upper lnterlock on thecontactor L which has been closed, w1re 57, contacts of the notchingrelay P, shunt coil of the relay P wire 51, wire 44 to the side of thesource. The completion of this circuit will take place only ifthecurrent in the series coil 29 has fallen to the value at which thecontacts of the relay P are closed. Closing of the contactor 1 shortcircuits a section of resistance R and thus increases the speed of themotor. The contactor 1 in closing clcsesits middle interlock, opens itslower one and closes its upper one, thereby shifting its actuating coll'from connection with the wire 56 to connection with the wire 44 leadingdirectly to the source, and also connecting the actuat ng coil of thecontactor '2 to the actuating wire 50.

Movement of the master switch through its other positions will result inclosing the resistance controlling contactors 2, 3, 4 and 5 under thecontrol of the notching relays P and 1 in the manner set forth in theCubitt application above referred to. It

will, therefore, be understood from the foregoing that it is necessaryfor the operator to maintain the lever 20 in its outward or poweroperation position while the master switch is in its first five onpositions, in order to insure power operation. If, however, he moves themaster switch to its sixth position, one of the lugs 38 will cooperatewith the lever 20 and positively hold the same in its outward position,thereby allowing the operator to take his hand from the handle of themaster switch. it while the master switch is in one of its first'five onpositions the operator releases the handle, the circuit changing devicecontrolled by it will assume the position in which it is indicated inFigs. 1 and 3. This will result in momentarily opening all of thecontactors which have closed and in reversing the armature withreference to the series field and connecting the armature and fieldthrough all of the resistances in a closed circuit, as indicated in Fig.5. This is brought about in the following manner: When the master switchhandle is released, the lever 20, under the influence of the spring 23,forces the rod 1?, carrying the contact disks 27 to 30 inclusive, intothe position shown in Fig. 1, thereby moving the disks 27 and 29 out ofengagement with their coperating contacts and moving the disks 28 and 30into engagement with their cotiperating contacts. Thereupon, the wires47 and t8 are ole/energized and the contactors L, L and L open. At thesame time the control circuits for the resistance controlling contactors1 to 5 are also disconnected from the source. Closing of the circuitthrough the contactdisk 28 of the circuit changing device, however,immediately connects the wire 60 to the source and the actuating coil ofthe contactor D is energized through the interlock on the contactor L,which has closed. The circuit through the contact disk 28 also suppliescurrent to the finger at of the master switch to which the finger bisconnected through cooperating segments; from finger b a wire 61 leads tothe actuating coil of the contactor L thence through the lower interlockon the contactor I), the actuating coil of the contactor L, the

lower interlock on the latter to Wire 50, the contact of the notchingrelay P shunt coil of the relay P, wire 51, and wire 44 to the side ofthe source. The contactors L and L will, therefore, close and the motorwill be connected in the circuit illustrated in Fi 5 and above referredto. If the master switch is in its 2nd, 3rd, 4th or 5th ositions theclosing of the resistance control ing contactors 1.to 5 will take placeexactly as during power operation of the motor, except thatthe'energization of both the series coils 9 0 and p 0 will keep themotor current at a lower value than under power operation,

as explained above. Opening of the circuit. through the contact disk 29and closing of the circuit through the contact disk 30 results merely inshifting the control wire )2 for the magnet I)" of the magnetic brake,

from direct connection to the source to conbraking the magnetic brakewill be applied when all of theresistance in the dynamic braking circuithas been short circuited. The system can be so designed that by the timeall of the resistance has been short circuited in the dynamic brakingcircuit the motor will have come substantially to 'rest and the magneticbrake will, therefore, have but little more to do than to hold the motorand the driven mechanism at rest.

Whilel have shown but ,one particular system in which my invention maybe embodied, I do not, of course, intend to limit it either to thisparticularuse or to this particular arrangement, but aim to cover in theappended claims all modifications and forms of my invention which comewithin the scope thereof.

What I claim as new and desire to secure by Letters Patent of-{theUnited States, is

1. In combination} a motor, a controller for connecting said motor to asource of cur rent to regulatethe potential applied tosaid motor throughmore or less resistance for dynamic braking, a handle by which saidcontroller is operated, and means whereby release of the handle incertain on positions of the controller will connect themotor for thedynamic braking eifect corresponding to that posit-ion.

3. In combination, a motor, a controller ,for connecting said motor to asource of current, for regulating the potential applied to said motorand for short-circuiting said motor through more or less of thecontroller resistance for dynamic braking, a handle by which saidcontroller is operated, circuitchanging means for rendering thecontroller operative in the same positions for either power or brakingcontrol, and means carried by said handle operatively connected to saidcircuit-changing means.

4. In combination, a motor, a controller for connecting said motor to asource of current, for regulating the potential applied to said motorand for short-circuiting said motor through more or less resistance fordynamic braking, circuit-changing means cooperating with said controllerfor rendering it operative in the same positions for either power orbraking control, means for biasing said circuit-changing means to itsbraking position, a handle. for said controller, and means cooperatingwith said handle for moving said circuit-changing means to its powerposition.

5. In a system of motor control, a motor to be controlled, a controllercomprising a plurality of contactors for connecting said motor to asource of current, for regulating the potential applied to said motorand for short-circuiting said motor through more or less resistance fordynamic braking, a master switch for controlling the operation of saidcontactors, and means cooperating with said master switch for renderingit operative in the same positions for either power or braking control.

6. In a system of motor control,.a motor to be controlled, a controllercomprising a plurality of contactors for connecting said motor to asource of current, for regulating the potential applied to said motorand for short-circuitin the motor through more or less resistance I01dynamic braking, a master switch for controlling the operation of saidcontactors, circuit-changing means cooperating with said master switchfor rendering the latter operative in the same positions for eitherpower or braking control, a handle for said master switch, and meanscooperating with said handle for operating said circuit-changing means.

7. In a motor control system, amotor to be controlled, a plurality ofcontactors arranged for operation in succession to control the potentialapplied to said motor, electromagnetically operated means responsive tocurrent in the motor circuit for regulating the closing of saidcontactors, and auxillary magnetizing coils cooperating with saidcurrent responsive means only under certain conditions. in the motorcircuit for varying the eifect of said current responsive means.

8. In a system of motor control, a motor to be controlled, resistancetherefor, and a controller comprising a plurality of contactors forconnecting said motors to a source of current, for regulating thepotential applied to said motor and for shortcircuiting the motorthrough more or less resistance for dynamic braking, notching relaysarranged to control the successive closing of the potential controllingcontactors, and auxiliary series coils on said relays energized duringdynamic braking operation but not during power operation for modifyingthe effect of said notching relays. In witness whereof, I have hereuntoset my hand this 17th day ofJune, 1909.

HAROLD E. WHITE. Witnesses:

BENJAMIN B. HULL, HELEN Onronn.

